the architects of common core say there could be a rocky transition period. some kids could take years before they measure up to the new benchmarks of learning and thinking. >>> rehema ellis, not far from where we are in midtown manhattan. and stay tuned tomorrow, two exclusive interviews, president obama speaks with savannah guthrie, i'll sit down with governor romney to hear out their ideas on education. it is all part of our continuing coverage on the network and cable and on the web. >>> still ahead for us tonight. we have all heard the expression, "dying of a broken heart." well, tonight what experts are learning about the power of sadness. >>> and working hard to save a great and beloved species. >>> a family obituary in the new york times announcing the death of the mother of christi brinkley said her heart never survived losing her husband, who died before her by seven weeks. that is very common after the death of a long-time spouse. but is that worse than a medical condition, and could it be fatal as it often appears to be? our report from our chief